Here's the set-up, such as it is: The couldn't-be-more-British Berry - a whiskey-loving scoundrel with a rapist wit (no, really) and a silky smooth baritone vox - is employed as High Executioner to the King of England. He also may or may not be a direct descendant of Jack the Ripper. Fulcher - a moon-faced, socially awkward American with poor hand-eye coordination and a penchant for profoundly inappropriate bursts of surreal profanity - has somehow weaseled his way into a position as Berry's assistant, not to mention adjunct membership in the posh Hangman Gentleman's Club where much of the series takes place.
Although the two men couldn't be more different, the way they play off each other serves as both an excellent example and a postmodernist deconstruction of the stereotypical Brits-versus-Yanks dynamic.
For instance, while Berry clearly sees himself as an alpha-type upholder of certain manly virtues, he is also a broken human wreck. Whether he's being bested at fisticuffs by a mincing Negro tailor, pompously failing miserably on a trivia-based game show, or violently bullying old ladies and small dogs, we sense in Berry a certain resigned nihilism, nourished perhaps by a deep current of post-Edwardian melancholy at the loss of Empire... like James Bond with a gammy leg and acute alcoholic hepatitis.
Fulcher is equally monstrous, but for entirely different reasons. A rampaging Id to Berry's unctuous Super-Ego, Fulcher is a virtual whirlwind of bewildered frustration, a middle-aged man-child of apocalyptic ignorance whose gross incompetence is so incomprehensibly profound that Berry's mediocrity shines like gold in comparison. Hence their undeniable chemistry.
To the extent that Snuff Box is known at all, it's mostly through a couple of set pieces - unrelated to the overriding story arc - that became viral videos, chief among these being the brutal "Boyfriend" sketches...
...and the comparatively delightful "Rapper with a Baby" sketch.
This is unfortunate, because although the above sketches are very funny, they barely hint at the ice-cold, pitch-black perfection of the show from which they've been excised. There are moments in Snuff Box, such as a Mac versus PC argument that takes place literally on the gallows, that border on the Satanic.
In case you're wondering, that is as unqualified a recommendation as you're ever likely to get out of yours truly.
So go out and buy Snuff Box, which is now available on DVD in North America with a bunch of excellent extras, including a CD of Matt Berry's wonderful music created especially for the series. If you don't like it, you can always just donate it to the nearest orphanage. What with the population crisis getting so out of hand, God only knows we could use a few more serial killers around.